Fix: Remove session state modification after widget instantiation

- Removed attempt to clear question_input after submission to avoid Streamlit error
- Example questions now properly populate the input field when clicked
- Fixed 'StreamlitAPIException: cannot be modified after widget instantiation' error

app.py

@@ -431,9 +431,6 @@ def main():
                         'sources': sources
                     })
                     
-                    # Clear the input field after successful submission
-                    st.session_state.question_input = ""
-                    
                     # Success message
                     st.success("✅ Answer generated successfully! Check the chat history below.")